(CBS) — The issue of gun control is very real for parents who’ve lost loved ones. Chicago’s Cleo and Nate Pendleton joined other families in Washington D.C. to help launch the “Not One More” campaign.

“Our smart, motivated and beautiful daughter was shot and murdered in Harsh Park on Chicago’s South Side on January 29, 2013,” said Cleo Pendleton.

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Survivors of shootings in Newtown, Connecticut, Aurora, Colorado and Virginia Tech were on hand as well.

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Hadiya Pendleton was the victim of gang violence. The 15-year-old honor student was not the intended target.

“Being frustrated is not going to get anything done. The only thing that we can do is keep standing what we believe in and hopefully people will come and join our movement,” said Nate Pendleton.

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The “Not One More” campaign is the idea of Richard Martinez, who lost his son in the Santa Barbara college shooting last month.